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Arctodus
simus Yukonensis
Giant
short-faced bear
The "bulldog
bear" was the largest land carnivore in North America during the Pleistocene
epoch. Standing five feet tall at the shoulder, it could have reached 11 feet when up on its hind legs and could have weighed up to1500 pounds.
This bear was
taller, leaner, and more rangy in build compared to present day Kodiak bears.
But Arctodus
was larger overall, swifter and more lethal.
Short faced bears of
the genus Arctodus ranged from both coasts of North and South America. Today, the only living descendant of these powerful predators lives on in
the Andes foothills in
the form of the shy, forest- dwelling Spectacled Bear, which also has a short,
broad snout. The remains of the largest
Arctodus have been found in Alaska and the Canadian Yukon,
these are given the sub-species name yukonensis, which is the species I have depicted
here.
The unusual skull of
Arctodus exhibits features that point to a highly carnivorous way of life. The
skull's overall shape and dentition is reminiscent of a lion's, with large canine teeth and
specialized, carnassial (flesh- shearing) molars. Arctodus had a characteristic short muzzle with no discernable
forehead; the eye sockets were set wide apart and face forward and must have
given Arctodus excellent vision. The opening of the nasal passage was huge, and
points towards a keen sense of smell, and to the need to inhale great volumes of oxygen, probably during
pursuit of prey, or more likely to cover long distances to scavenge a carcass. The large width of the jaws in relation to
their shortness, plus the huge insertions for the pre-masseter, masseter and
temporalis muscles gave this bear a vise-like crushing bite.
Arctodus was
exceptionally long legged, and unlike modern bears,
the toe bones of Arctodus articulate straight out in front so they were not
pigeon-toed. This gave Arctodus an efficient pacing gait. Pacing involves moving
both the front and back feet on one side in unison with each other.
Like so much of the Pleistocene
megafauna, the record of the short-faced bear stops at end of the last ice age
around 10,000 years ago.
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